U.S. patent number 4,787,608 [Application Number 07/003,513] was granted by the patent office on 1988-11-29 for nylon bead reinforcement ring for fluid pressure devices.
This patent grant is currently assigned to The Firestone Tire & Rubber Company. Invention is credited to Robert F. Elliott.
United States Patent |
4,787,608 |
Elliott |
November 29, 1988 |
Nylon bead reinforcement ring for fluid pressure devices
Abstract
Air springs or other fluid pressure devices have flexible
elastomeric sleeves terminating in a pair of end beads which are
clamped or crimped onto a pair of spaced end members. Each of the
beads is reinforced by a solid annular ring of nonreinforced
thermoplastic material which is molded within the sleeve beads. The
rings preferably are formed of nylon and are sufficiently flexible
to move with the end members and sleeve and return to their
original shape after such movement. A similar nonreinforced plastic
ring may be molded in a central portion of the elastomer sleeve to
provide the girdle hoop of the sleeve.
Inventors: |
Elliott; Robert F. (Westfield,
IN) |
Assignee: |
The Firestone Tire & Rubber
Company (Akron, OH)
|
Family
ID: |
21706219 |
Appl.
No.: |
07/003,513 |
Filed: |
January 15, 1987 |
Current U.S.
Class: |
267/64.27; 92/47;
152/540; 152/452; 267/64.19 |
Current CPC
Class: |
F16F
9/0454 (20130101) |
Current International
Class: |
F16F
9/04 (20060101); F16F 9/02 (20060101); F16F
009/04 (); F16J 003/00 (); B60C 005/01 (); B60C
015/00 () |
Field of
Search: |
;267/64.27,64.24,64.23,64.21,64.19,152,153,292 ;188/298
;92/46,47,41,13F,13SD ;152/547,540,539,452,544,527 ;524/471
;280/711,714 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0226552 |
|
Aug 1958 |
|
AU |
|
732494 |
|
Apr 1966 |
|
CA |
|
2609392 |
|
Sep 1977 |
|
DE |
|
2904521 |
|
Aug 1980 |
|
DE |
|
3007772 |
|
Sep 1981 |
|
DE |
|
55-127210 |
|
Jan 1980 |
|
JP |
|
0066007 |
|
Apr 1982 |
|
JP |
|
861469 |
|
Jul 1957 |
|
GB |
|
0819728 |
|
Sep 1959 |
|
GB |
|
2117866 |
|
Oct 1983 |
|
GB |
|
Primary Examiner: Kashnikow; Andres
Assistant Examiner: Oberleitner; Robert J.
Attorney, Agent or Firm: Brietkrenz; Ronald
Claims
What is claimed is:
1. A fluid pressure device including a pair of spaced end members
and an intervening flexible elastomeric sleeve forming a fluid
pressure chamber therein; a solid one-piece bead ring having a
uniform cross section formed of a nonreinforced nylon and molded
within each of the ends of the elastomeric sleeve, said bead rings
being free of any interconnecting reinforcing members extending
therebetween and connected to said bead rings; and said spaced end
members each having an annular rolled end crimped about a
respective one of the bead rings forming a fluid tight seal
therebetween.
2. The fluid pressure device defined in claim 1 in which the nylon
is an aliphatic nylon.
3. The fluid pressure device defined in claim 1 in which a third
ring of nonreinforced thermoplastic material is molded in the
elastomeric sleeve intermediate the two end rings.
4. The fluid pressure device defined in claim 1 in which the nylon
is nylon 66 having a tensile strength and yield strength of
approximately 13,600 psi at 73.degree. F. and a high flexural
modulus of approximately 470,000 psi at 73.degree. F.
5. The fluid pressure device defined in claim 4 in which the nylon
has a melting point of approximately 495.degree. F. with a
deflection temperature at 66 psi of 425.degree. F. and at 264 psi
of 171.degree. F.
6. The fluid pressure device defined in claim 1 in which each of
the bead rings is circular in cross section.
Description
TECHNICAL FIELD
The invention relates to flexible elastomeric sleeves used in fluid
pressure devices, and in particular to a plastic ring for
reinforcing the annular beads or for the formation of a girdle hoop
of the elastomeric sleeve of an air spring.
BACKGROUND ART
Flexible elastomeric sleeves are used in various types of fluid
pressure systems and devices such as air springs which are used as
both vibration isolators and actuators. These pneumatic devices or
air springs as they are commonly referred to are used for a variety
of applications. One particular application is providing cushioning
or vibration isolation between movable parts of a vehicle to absorb
shock loads impressed on the vehicle axis by the wheels striking an
object on the road or entering into a depression. Many of these
devices also are used as actuators to provide movement between two
parts of a machine or piece of equipment.
Most of these air springs have annular beads at the ends of a
flexible elastomeric sleeve which forms a fluid pressure chamber,
which beads are clamped or crimped onto rigid end members or end
plates. The end members are mounted on spaced portions of a vehicle
or other equipment on which the air springs are mounted. Currently,
these beads are internally reinforced with high strength wire which
is wound into a continuous diameter or ring and then molded within
the ends of the flexible sleeves to assist in maintaining the
sleeve beads in an airtight sealing relationship with the end
members. These bands are also molded into a midpoint of the sleeves
to form a girdle hoop therefor for certain applications.
Although these prior steel band or wire reinforced beads and girdle
hoops are satisfactory, they increase the weight of the air spring
and increase the cost of the device due to the expense of the wire.
Also, additional manufacturing costs are required for forming the
wire into an annular band prior to molding it within the ends or
midsection of the elastomeric sleeve.
Some examples of prior art devices using a reinforced bead are
shown in the following patents.
U.S. Pat. No. 3,897,941 shows a type of flexible resilient tubular
member used in a fluid pressure system having a reinforced bead in
which the reinforcement is an annular metal band located at each
end of the resilient member.
U.S. Pat. No. 3,237,674 discloses a reinforcing bead ring used as
part of a bead assembly for pneumatic tires in which the bead
assembly has a resin-impregnated glass fiber material combined with
an epoxy resin matrix and molded into a hoop-like configuration
which is molded within the bead area of a pneumatic tire.
U.S. Pat. No. 4,168,193 discloses a tire bead ring configuration in
which a generally annular ring is held in place within a filled
rubber compound which has been injection molded to provide
reinforcement of a tire bead. The bead core is indicated as being
strands of wire or fiberglass.
U.S. Pat. No. 4,231,408 discloses a tire having a plurality of
elongated reinforcing members mounted in the sidewall area of the
tire which are formed as a single unit of a wire reinforced rubber
tape, rayon, nylon, polyester, aramid, fiberglass, steel, bronze
coated steel, or the like.
Japanese Pat. No. 55-127210 discloses a bead wire formed with a
circular cross sectional configuration or a six-sided
configuration.
Although the prior bead reinforcements and girdle hoops formed of
wire have proved satisfactory, they increase the cost of the fluid
pressure device and the weight thereof. Attempts have been made to
form the bead of a fiber reinforced synthetic material but such
reinforcements have been found to be unsatisfactory due to the
brittleness and stiffness of the bead ring preventing it from
flexing sufficiently with the movement of the fluid pressure
device.
Therefore the need has existed for a reinforcing ring used as a
bead reinforcement or girdle hoop which is less expensive to
manufacture and lighterweight than existing metal bands, and which
is sufficiently flexible to move repeatedly with the flexible
elastomeric sleeve without breaking.
DISCLOSURE OF THE INVENTION
Objectives of the invention include providing a plastic
reinforcement ring for a fluid pressure device and in particular
for an air spring, in which the ring is a solid nonreinforced
member formed of a thermoplastic, preferably nylon, which is molded
within the bead ends of a flexible elastomeric sleeve which is
adapted to be clamped or crimped to spaced end plates or end
members to provide an internal fluid pressure chamber. Another
objective is to provide such an improved bead reinforcement
primarily for use on air springs replacing the heretofore more
expensive and heavier wire strand bead reinforcement.
A still further objective of the invention is to provide an
improved bead reinforcement which is formed of a solid
nonreinforced thermoplastic material which enables the ring to flex
and move with the movements of the flexible sleeve and end mounting
plates and absorb the forces continuously exerted on the pressure
device without becoming brittle or breaking, and which has
sufficient flexibility and material memory permitting the ring to
return to its natural unstressed state.
Another objective is to provide such an improved reinforcement ring
which can be injection molded in a simple, inexpensive and mass
production type of manufacturing operation thereby reducing the
cost of the ring, and in which the reinforcement ring can be molded
into the bead areas of the elastomeric sleeve simply and easily
without the molding operation effecting the operating
characteristics of the ring, and which results in a lighter weight
fluid pressure device.
A further objective is to provide such an improved reinforcement
ring which can be molded into the flexible elastomeric sleeve,
intermediate the bead ends, to provide the girdle hoop therefor
replacing the heretofore metal ring required for such a girdle hoop
construction, again reducing the weight and cost of the final fluid
pressure device.
These objectives and advantages are achieved by the improved
reinforcement ring construction which is adapted to be mounted in a
fluid pressure device of the type having a pair of spaced end
members and an intervening flexible sleeve, and a pair of annular
end beads connected to said end members for forming a fluid
pressure therebetween, in which the improvement includes providing
an annular solid thermoplastic bead ring molded within the end
beads of said sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention, illustrative of the best
modes in which applicant has contemplated applying the principles,
are set forth in the following description and are shown in the
drawings and are particularly and distinctly pointed out and set
forth in the appended claims.
FIG. 1 is a plan view of the improved plastic reinforcement ring of
the invention;
FIG. 2 is an end elevational view of the reinforcement ring of FIG.
1;
FIG. 3 is a greatly enlarged sectional view taken on line 3--3,
FIG. 1;
FIG. 4 is an elevational view with portions broken away and in
section, of an air spring having the improved reinforcement ring
incorporated in the end beads thereof; and
FIG. 5 is an elevational view with portions broken away and in
section similar to FIG. 4, showing the improved reinforcement ring
being used as a girdle hoop in the flexible sleeve of an air
spring.
Similar numerals refer to similar parts throughout the
drawings.
BEST MODE FOR CARRYING OUT THE INVENTION
The improved reinforcement ring is indicated generally at 1, and is
an annular band or ring molded of a solid non-reinforced
thermoplastic material, preferably uniformly in cross section as
shown in FIG. 3. Ring 1 will have a thickness and diameter
compatible with the particular fluid pressure device with which it
is intended to be used.
A usual fluid pressure device with which bead ring 1 will be used
is shown in FIG. 4. The device is an air spring and is indicated
generally at 2, and has upper and lower end plates, indicated
generally at 3 and 4, which are formed of stamped steel or similar
material, having rolled ends 5 and 6, respectively. The rolled ends
are crimped about annular beads 7 formed integrally on the ends of
a hollow flexible elastomeric sleeve indicated generally at 10,
which forms a fluid pressure chamber 11 therein.
End plates 3 and 4 may be formed with internally threaded bosses 13
for receiving threaded fasteners (not shown) for mounting the end
plates on a supporting structure. A threaded hole 14 also may be
formed in one or both of the end plates to provide an access
opening for the pressurized air or other fluid of fluid pressure
chamber 11. End plates 3 and 4 may have other configurations than
that shown in FIG. 4 without effecting the concept of the invention
and are components well known in the art. Furthermore, the improved
plastic reinforcement ring of the invention may be used with other
types of fluid pressure devices and systems which are similar in
many respects to air spring 2 shown in FIG. 4. Air spring 2 is used
as an illustration of the type of device with which the improved
bead reinforcement is intended to be incorporated.
In accordance with one of the main features of the invention, it
has been discovered that formation of reinforcement ring 1 of a
solid nonreinforced high strength thermoplastic material provides
an annular ring which has sufficient flexibility to be compatible
with the final device, which enables the ring to move in various
directions upon forces being exerted on the device, while
possessing sufficient material memory whereby it returns to its
unstressed position without breaking or deforming. Examples of
thermoplastic compounds include nylon, that is polyamide,
polyester, polyurethane, and the like. The nylons are preferred for
use in the present invention and include nylons made from internal
lactams, as well as nylons made from diamines and dibasic acids.
The nylon made from hexamethylenediamine and adipic acid (nylon 66)
is preferred. A suitable nylon 66 type which has been found to be
very suitable in the present invention is a controlled
cyrstalization nylon sold under the designation Nylon 1310 by
Celanese Corporation. This nylon generally has a comparatively high
tensile strength, for example 13,600 psi at 73.degree. F., a very
high yield strength, approximately 13,600 psi at 73.degree. F. as
well as a high flexural modulus, that is approximately 470,000 psi
at 73.degree. F. The melting point of this particular nylon is
approximately 495.degree. F. with a deflection temperature at 66
psi of 425.degree. F. and at 264 psi of 171.degree. F.
Another improved fluid pressure device, indicated generally at 15,
having a reinforcement ring incorporated therein is shown in FIG. 5
and is an air spring similar to that of FIG. 4 with the addition of
a girdle hoop 16. Hoop 16 is formed of the same nonreinforced
thermoplastic material as is ring 1 described above and is molded
integrally within sidewall 18 of a flexible sleeve 17 during the
formation thereof. Heretofore, such girdle hoops were formed of the
same metal wire as the wire bead reinforcement band and have the
same disadvantages, that is, increased manufacturing costs and
increased weight to the final product. Girdle hoop 16 can be molded
into sleeve sidewall 18 simultaneously with the molding of bead
rings 1 in beads 7.
The thickness of the bead reinforcement ring may vary in
relationship to the diameter of the ring in order to meet various
application criterion. When used in air spring applications such as
shown in FIG. 4, it has been found that bead ring 1 has a thickness
of approximately 0.125 inches with a nominal ring diameter of
approximately 3.5 inches and may have an increased thickness of
approximately 0.156 inches for rings having diameters in the range
of 4.28 inches up to and including diameters of 10.3 inches.
Accordingly, it has been found that the improved bead reinforcement
ring as set forth above, when incorporated into a fluid pressure
device in the bead area and/or midpoint area of the flexible
elastomeric sleeve, provides a device lighter in weight, less
expensive to manufacture, without sacrificing the operating
characteristics, efficiency and life of the device.
Accordingly, the improved plastic reinforcement ring is simplified,
provides an effective, safe, inexpensive, and efficient device
which achieves all the enumerated objectives, provides for
eliminating difficulties encountered with prior devices, and solves
problems and obtains new results in the art.
In the foregoing description, certain terms have been used for
brevity, clearness and understanding; but no unnecessary
limitations are to be implied therefrom beyond the requirements of
the prior art, because such terms are used for descriptive purposes
and are intended to be broadly construed.
Moreover, the description and illustration of the invention is by
way of example, and the scope of the invention is not limited to
the exact details shown or described.
Having now described the features, discoveries and principles of
the invention, the manner in which the improved plastic
reinforcement ring for fluid pressure devices is constructed and
used, the characteristics of the construction, and the
advantageous, new and useful results obtained; the new and useful
structures, devices, elements, arrangements, parts, and
combinations, are set forth in the appended claims.
* * * * *